Ball-grid-array semiconductor with protruding terminals

ABSTRACT

There is provided a ball-grid-array semiconductor device. The semiconductor device has a semiconductor element sealed with a resin material. In addition, a lead frame is connected to the semiconductor element in the resin material. The lead frame is provided with terminal portions that protrude through the surface of the resin material.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a ball-grid-array semiconductordevice and a manufacturing method therefor, and more particularly, to aball-grid-array semiconductor device having a lead frame with terminalportions formed to protrude by etching, and its manufacturing method.

[0003] 2. Description of the Related Art

[0004] A package including a lead frame is available as one ofsemiconductor device packages that have been manufactured to meet therequirements for semiconductor devices such as higher-integration,miniaturization, decreasing in thickness, and higher pin count. Atechnique relating to a method for manufacturing lead frames that isapplicable to ball-grid-array semiconductor devices is described inJapanese Patent Application Laid-Open No. Sho 60 (1985)-52050. FIG. 1 isa cross-sectional view showing a conventional semiconductor devicehaving a lead frame described in Japanese Patent Application Laid-OpenNo. Sho 60 (1985)-52050.

[0005] According to the prior art described in this publication, in aprocess where a sheet of metal is etched to form a lead frame,approximately a half of one side of the metal sheet is etched. Thisallows for forming projected portions 110 a for use as externalterminals on the side, which protrude in the direction of thickness ofthe metal sheet. Subsequently, an integrated circuit 114 is attachedwith a bonding portion 112 to the other side where the projectedportions 110 a of the lead frame 110 have not been formed. Then, theseare sealed with resin 118. At this time, edges of the projected portions110 a and part of the sides of the resin 118 are coplanar. For theconventional semiconductor devices, such method was employed tomanufacture the lead frame 110 having terminals for external connectionin one process.

[0006] However, this presents a problem that it is difficult to cleanflux residues remaining between a package and a substrate after thepackage has been mounted onto the substrate. This happens because theedges of the projected portions 110 a, or external terminals, and partof sides of the resin 118 are coplanar.

[0007] A method of mounting solder balls onto the projected portions 110a is available to solve this problem, however, this method also presentsa problem that material and manufacturing costs are hardly reduced.

SUMMARY OF THE INVENTION

[0008] An object of the present invention is to provide aball-grid-array semiconductor device and manufacturing method therefor,which facilitates cleaning flux residues remaining in between thepackage and the substrate after having been mounted onto the substrate,and which provides drastically reduced material and manufacturing costs.

[0009] According to one aspect of the present invention, aball-grid-array semiconductor device comprises: a semiconductor element;a resin material which seals the semiconductor element; and a lead frameconnected to the semiconductor element in the resin material. The leadframe has a terminal portion that protrudes through a surface of theresin material.

[0010] According to another aspect of the present invention, a methodfor manufacturing a ball-grid-array semiconductor device comprises thesteps of: forming a lead frame having a terminal portion that protrudesin the direction of thickness thereof; mounting a semiconductor elementon the lead frame; connecting an electrode provided on the semiconductordevice to the lead frame by means of a bonding wire; and sealing thesemiconductor element with a resin material. The terminal portionprotrudes through a surface of the resin material.

[0011] The present invention allows the terminal portions to protrudethrough the surface of the resin material. Thus, the terminal portionscan used as connecting terminals, as they are, to be mounted directly tothe substrate, and cleaning of flux residues after mounting can bereadily carried out. Therefore, conventional ball-grid-arraysemiconductor devices have required solder balls to be mounted onpackages to facilitate cleaning flux residues, whereas the presentinvention requires no such necessity, allowing for providing remarkablyreduced material and manufacturing costs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a cross-sectional view showing a conventionalsemiconductor device having a lead frame described in Japanese PatentApplication Laid-Open No. Sho 60 (1985)-52050.

[0013]FIG. 2 is a cross-sectional view showing the structure of aball-grid-array semiconductor device according to an embodiment of thepresent invention.

[0014]FIG. 3 is a bottom view showing the structure of theball-grid-array semiconductor device according to the embodiment of thepresent invention.

[0015]FIG. 4 is a view showing the method for manufacturing theball-grid-array semiconductor device according to the embodiment of thepresent invention, illustrating the step where the device is sealed withresin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The embodiment of the present invention is to be explainedspecifically with reference to the accompanying drawings. FIG. 2 is across-sectional view showing the structure of a ball-grid-arraysemiconductor device according to the embodiment of the presentinvention. FIG. 3 is a bottom view showing the structure of theball-grid-array semiconductor device similarly according to theembodiment of the present invention.

[0017] A ball-grid-array semiconductor device 1 according to thisembodiment allows a semiconductor element 14 to be mounted with anadhesive tape 12 on a lead frame 10 provided with terminal portions 10 awhich protrude in the direction of thickness thereof. The lead frame 10is formed, for example, by etching a sheet of metal approximately a halfof the thickness thereof.

[0018] Moreover, bonding wires 16 connect the lead frame 10 toelectrodes provided on the semiconductor element 14. Then, they aresealed with a resin material 18 to be formed in a predetermined packageshape. Incidentally, the terminal portions 10 a protrude through thesubstrate mount surface of the resin material 18. Moreover, a solderlayer 19 is formed on the edges of the terminal portions 10 a.

[0019] The ball-grid-array semiconductor device 1 of this embodimentconstructed as such allows the terminal portions 10 a, on which thesolder layer 19 is formed, to be used as terminals as they are for beingmounted on a substrate.

[0020] Incidentally, the terminal portions 10 a can be etched into avariety of shapes such as a cylinder or a rectangular column. However, acylindrical shape is desirable in which stress is unlikely to occur,when considering the heat-cycle resisting performance thereof afterhaving been mounted on the substrate.

[0021] In addition, the terminal portions 10 a have desirably a heightranging from 0.1 to 0.3 mm from the substrate mount surface, whenconsidering the easiness of cleaning flux residues after having beenmounted.

[0022] Furthermore, the solder layer 19 to be formed on the edges ofterminal portions 10 a is desirably about 5 to 10 μm in thickness, whichis equivalent in thickness to a solder layer to be applied to outerleads of resin-sealed semiconductor devices, typified by conventionalQFP (Quad Flat Pack) semiconductor devices.

[0023] Next, a method for manufacturing the aforementioned semiconductordevice of this embodiment is to be explained. FIG. 4 is across-sectional view showing the method for manufacturing theball-grid-array semiconductor device according to the embodiment of thepresent invention, illustrating the step where the device is sealed withresin.

[0024] First, a sheet of metal is etched approximately by half thethickness thereof to form a lead frame 10 having the terminal portions10 a that protrude in the direction of thickness. Subsequently, asemiconductor element 14 is mounted onto the lead frame 10 with anadhesive tape. Then, the electrodes provided on the semiconductorelement 14 are connected to the lead frame 10 by means of bonding wires16.

[0025] Subsequently, as shown in FIG. 4, the lead frame 10, thesemiconductor element 14 and the like are sandwiched in between an uppermetal mold 22 having a cavity 22 a of a predetermined shape and a lowermetal mold 20 having recessed portions 20 a as a cavity foraccommodating the terminal portions 10 a. Then, resin is allowed to flowin from an injection portion (not shown) which is in connection with thecavities 20 a and 22 a, thereby sealing the lead frame 10 and thesemiconductor element 14 with the resin.

[0026] After the encapsulation with the resin has been completed, therewill exist thin fins on the edges of the terminal portions 10 a. Thus,those thin fins are removed by laser honing, sand blasting, water jethoning or the like in order to allow the terminal portions 10 a of thelead frame 10 to be exposed. Thereafter, a solder layer 19 is formed onthe edges of the terminal portions 10 a.

[0027] Such method as mentioned above allows the terminal portions 10 aof the lead frame 10 to protrude through the substrate mount surface ofthe resin material 18.

[0028] As described above, this embodiment allows the terminal portions10 a to protrude through the substrate mount surface of the package andthe solder layer 19 to be formed on the edges thereof. Therefore, theterminal portions 10 a can be used as connecting terminals, as they are,for being mounted directly to the substrate, and the cleaning of fluxresidues after the portions have been mounted can be readily carriedout. Therefore, conventional ball-grid-array semiconductor devices haverequired solder balls to be mounted on packages to facilitate cleaningflux residues, whereas this embodiment requires no such necessity,allowing for providing remarkably reduced material and manufacturingcosts.

What is claimed is:
 1. A ball-grid-array semiconductor devicecomprising: a semiconductor element; a resin material which seals saidsemiconductor element; and a lead frame connected to said semiconductorelement in said resin material, said lead frame having a terminalportion that protrudes through a surface of said resin material.
 2. Theball-grid-array semiconductor device according to claim 1 , whichfurther comprising a solder layer formed on an edge surface of saidterminal portion.
 3. The ball-grid-array semiconductor device accordingto claim 1 , which further comprising a bonding wire which connects saidsemiconductor element to said lead frame.
 4. The ball-grid-arraysemiconductor device according to claim 1 , wherein said terminalportion is formed by etching a sheet of metal, a material of said leadframe, substantially half of the thickness thereof.
 5. A method formanufacturing a ball-grid-array semiconductor device, comprising thesteps of: forming a lead frame having a terminal portion that protrudesin the direction of thickness thereof; mounting a semiconductor elementon said lead frame; connecting an electrode provided on saidsemiconductor device to the lead frame by means of a bonding wire; andsealing said semiconductor element with a resin material, said terminalportion protruding through a surface of said resin material.
 6. Themethod for manufacturing a ball-grid-array semiconductor deviceaccording to claim 5 , which further comprising the step of forming asolder layer on an edge surface of said terminal portions.
 7. The methodfor manufacturing a ball-grid-array semiconductor device according toclaim 5 , wherein the step of forming said lead frame comprises the stepof etching a sheet of metal substantially half of the thickness thereof.